L-Lactide

Conditions: temp:160.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A flame dried, 250 mL, round bottom single neck flask was charged with 57.1 grams (0.50 mole) of ε-caprolactone, 72.1 grams (0.50 mole) of L-lactide, 4.00 mL (55 mmol) of distilled glycerol, and 0.10 mL (34 pmol) of a 0.33M stannous octoate solution in toluene. The flask was fitted with a flame dried mechanical stirrer. The reactor was purged with nitrogen three times before venting with nitrogen. The reaction mixture was heated to 160° C. and maintained at this temperature for about 18-20 hours. The copolymer was dried under vacuum (0.1 mm Hg) at 110° C. for about 16 hours to remove any unreacted monomer. The copolymer had an inherent viscosity of 0.14 dL/g in hexafluoroisoproponal (HFIP) at 25° C. The copolymer was a liquid at room temperature. The molar ratio of PCL/PLA was found to be 53.7/46.3 by proton NMR. A flame dried The flask was fitted with a flame dried mechanical stirrer The reactor was purged with nitrogen three times maintained at this temperature for about 18-20 hours The copolymer was dried under vacuum (0.1 mm Hg) at 110° C. for about 16 hours to remove any unreacted monomer at 25° C at room temperature

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The same procedure as in Preparation Example 4 was effected except that 6 mols of L-lactide and 14 mols of ε-caprolactone were used, thereby obtaining a lactic acid-hydroxycaproic acid copolymer (hereinafter referred to as "PCLA2"). This PCLA2 had a weight average molecular weight of 72000, and a molar ratio of a lactic acid unit to a hydroxycaproic acid unit in the copolymer was 33 to 67. The same procedure as in Preparation Example 4

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The same procedure as in Preparation Example 3 was effected except that 1441 g (10 mols) of L-lactide, 1140 g (10 mols) of ε-caprolactone and 10 ml of a toluene solution containing 0.26 g of stannous octoate, and 5 g of lauryl alcohol were used and that reaction was carried out at 160° C. for 10 hours, thereby obtaining a lactic acid-hydroxycaproic acid copolymer (hereinafter referred to as "PCLA1"). The same procedure as in Preparation Example 3 were used and that reaction

Conditions: temp:220.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1161 g (10 mols) of glycolide and 1441 g (10 mols) of L-lactide were placed in a glass reactor, and 10 ml of a toluene solution containing 0.26 g of stannous octoate and 9.0 g of lauryl alcohol were added to the reactor. Afterward, deaeration was carried out for 2 hours under reduced pressure, and the atmosphere in the reactor was then replaced with a nitrogen gas. This mixture was heated at 220° C. for 2 hours with stirring under the nitrogen atmosphere. While the temperature was maintained as it was, the deaeration was slowly performed by means of a vacuum pump through an exhaust pipe to reduce the pressure in the reactor to 3 mm Hg. One hour after the start of the deaeration, the monomers and low-molecular substances were not extracted any more, and the interior of the reactor was replaced with nitrogen and a resultant glycolic acid-lactic acid copolymer (hereinafter referred to as "PLGA") was then taken out. were added to the reactor While the temperature was maintained as it One hour after the start of the deaeration, the monomers and low-molecular substances were not extracted any more, and the interior of the reactor

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The procedure of Example II is repeated except that 20 grams of L-(-)-lactide, 30 grams of epsilon caprolactone and 0.0105 grams of pure stannous octoate are placed in a glass flask, blanketed with nitrogen, and heated for 45 hours at 140° to 142° C. The copolymer is tough and elastic and has good tensile strength and elongation properties. The copolymer has a GPC molecular weight of Mw =323,000 and Mn =180,000. DSC of the copolymer reveals a moderate amount of crystallinity with a melting point endo-therm of 42° C. and a glass transition temperature of -16° C. Physical properties of the polymer are shown in Table 1. are placed in a glass flask heated for 45 hours at 140° to 142° C with a melting point endo-therm of 42° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The procedure of Example II is repeated except that 15 grams of L-(-)-lactide, 35 grams of epsilon caprolactone and 0.0105 grams of pure stannous octoate catalyst are blanketed with dry nitrogen in a glass flask and heated for 45 hours at 140° to 142° C. The copolymer is tough and elastic and has good tensile strength and elongation properties. The copolymer has are blanketed with dry nitrogen in a glass flask heated for 45 hours at 140° to 142° C

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Dextran-(2-hydroxyethylmethacrylate)-lactate (Dex-lactateHEMA) macromer was synthesized according to a published method (Wolthuis, et al. Polymer, 1997, 38, 6235-6242). For example, L-lactide and 2-hydroxyethyl methacrylate (HEMA) with 1:1 molar ratio were first reacted at 110° C. for one hour in the presence of catalyst SnOct2 to obtain HEMA-lactate. Secondly, N,N′-carbonyldiimidazole (CDI) was reacted with the above HEMA-lactate product at 1:1 feeding molar ratio at room temperature in THF for 16 h to obtain HEMA-lactateCI. Finally, a calculated amount of dextran was reacted with HEMA-lactateCI (HEMAlactateCI:glucopyranose=7:1 molar ratio) in the presence of catalyst 4-(N,N-dimethylamino) pyridine (DMAP) in dimethyl sulfoxide (DMSO) at room temperature for four days to obtain the Dex-lactateHEMA macromer. The average length of lactate spacer (DPav) is equal to 3, and degree of substitute (DS; amount of methacrylate groups per 100 dextran glucopyranose residues) is equal to 4.6. were first reacted at 110° C. for one hour in the presence of catalyst SnOct2

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Dextran-(2-hydroxyethylmethacrylate)-lactate (Dex-lactateHEMA) macromer was synthesized according to a published method (Wolthuis, et al. Polymer, 1997, 38, 6235-6242). For example, L-lactide and 2-hydroxyethyl methacrylate (HEMA) with 1:1 molar ratio were first reacted at 110° C. for one hour in the presence of catalyst SnOct2 to obtain HEMA-lactate. Secondly, N,N′-carbonyldiimidazole (CDI) was reacted with the above HEMA-lactate product at 1:1 feeding molar ratio at room temperature in THF for 16 h to obtain HEMA-lactateCI. Finally, a calculated amount of dextran was reacted with HEMA-lactateCI (HEMAlactateCI:glucopyranose=7:1 molar ratio) in the presence of catalyst 4-(N,N-dimethylamino) pyridine (DMAP) in dimethyl sulfoxide (DMSO) at room temperature for four days to obtain the Dex-lactateHEMA macromer. The average length of lactate spacer (DPav) is equal to 3, and degree of substitute (DS; amount of methacrylate groups per 100 dextran glucopyranose residues) is equal to 4.6. were first reacted at 110° C. for one hour in the presence of catalyst SnOct2

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: L-Lactide (85.07 g; 0.945 moles) and water (100 mL; millipore) were placed in a 1 L 3-neck flask equipped with a mechanical stirrer, distillation head, and a thermometer. The reaction mixture was warmed to 80° C. and stirred under nitrogen overnight. The flask was then placed under vacuum (aspirator, 7 mmHg) and the temperature was raised to 140° C. to distill off water. After 2 hrs trimethylene carbonate (8.51 g, 0.083 moles) was added. Two hours later a second portion of trimethylene carbonate (8.52 g, 0.083 moles) was added and the reaction was allowed to proceed for 3 more hours. The reaction was cooled to 80° C. and 120 mL of acetic anhydride was added. The solution was stirred at 80° C. overnight under a slow nitrogen purge. After 18 hours the remaining acetic anhydride and acetic acid were removed under vacuum. After the acetic acid and acetic anhydride distillation was complete, 180 mL of tetrahydrofuran/water (85/15; v/v) was added with stirring and the flask temperature was allowed to drop to 60° C. After 15 min the reaction mixture was transferred to a round bottom flask and the tetrahydrofuran was removed under vacuum on a rotary evaporator. Chloroform (300 mL) was added and the resulting solution was extracted twice with 150 mL of millipore water in a separatory funnel and then dried with MgSO4. The mixture was filtered through a "d" fritted glass funnel and the solvent distilled from the oligomer by rotary evaporation. Final traces of solvents were removed under high vacuum (0.4 mmHg) on a Kugelrohr apparatus at 90° C. to yield acetyl-oligo(L-lactic acid-co-trimethylene carbonate) with trimethylene carbonate n=1.6, lactic acid n=7.6, MN =974, and MW =1684. equipped with a mechanical stirrer distillation head the temperature was raised to 140° C. to distill off water The reaction was cooled to 80° C. The solution was stirred at 80° C. overnight under a slow nitrogen purge After 18 hours the remaining acetic anhydride and acetic acid were removed under vacuum After the acetic acid and acetic anhydride distillation 180 mL of tetrahydrofuran/water (85/15; v/v) was added with stirring to drop to 60° C After 15 min the reaction mixture was transferred to a round bottom flask the tetrahydrofuran was removed under vacuum on a rotary evaporator Chloroform (300 mL) was added the resulting solution was extracted twice with 150 mL of millipore water in a separatory funnel dried with MgSO4 The mixture was filtered through a "d" fritted glass funnel the solvent distilled from the oligomer by rotary evaporation Final traces of solvents were removed under high vacuum (0.4 mmHg) on a Kugelrohr apparatus at 90° C.

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: L-Lactide (85.07 g; 0.945 moles) and water (100 mL; millipore) were placed in a 1 L 3-neck flask equipped with a mechanical stirrer, distillation head, and a thermometer. The reaction mixture was warmed to 80° C. and stirred under nitrogen overnight. The flask was then placed under vacuum (aspirator, 7 mmHg) and the temperature was raised to 140° C. to distill off water. After 2 hrs trimethylene carbonate (8.51 g, 0.083 moles) was added. Two hours later a second portion of trimethylene carbonate (8.52 g, 0.083 moles) was added and the reaction was allowed to proceed for 3 more hours. The reaction was cooled to 80° C. and 120 mL of acetic anhydride was added. The solution was stirred at 80° C. overnight under a slow nitrogen purge. After 18 hours the remaining acetic anhydride and acetic acid were removed under vacuum. After the acetic acid and acetic anhydride distillation was complete, 180 mL of tetrahydrofuran/water (85/15; v/v) was added with stirring and the flask temperature was allowed to drop to 60° C. After 15 min the reaction mixture was transferred to a round bottom flask and the tetrahydrofuran was removed under vacuum on a rotary evaporator. Chloroform (300 mL) was added and the resulting solution was extracted twice with 150 mL of millipore water in a separatory funnel and then dried with MgSO4. The mixture was filtered through a "d" fritted glass funnel and the solvent distilled from the oligomer by rotary evaporation. Final traces of solvents were removed under high vacuum (0.4 mmHg) on a Kugelrohr apparatus at 90° C. to yield acetyl-oligo(L-lactic acid-co-trimethylene carbonate) with trimethylene carbonate n=1.6, lactic acid n=7.6, MN =974, and MW =1684. equipped with a mechanical stirrer distillation head the temperature was raised to 140° C. to distill off water The reaction was cooled to 80° C. The solution was stirred at 80° C. overnight under a slow nitrogen purge After 18 hours the remaining acetic anhydride and acetic acid were removed under vacuum After the acetic acid and acetic anhydride distillation 180 mL of tetrahydrofuran/water (85/15; v/v) was added with stirring to drop to 60° C After 15 min the reaction mixture was transferred to a round bottom flask the tetrahydrofuran was removed under vacuum on a rotary evaporator Chloroform (300 mL) was added the resulting solution was extracted twice with 150 mL of millipore water in a separatory funnel dried with MgSO4 The mixture was filtered through a "d" fritted glass funnel the solvent distilled from the oligomer by rotary evaporation Final traces of solvents were removed under high vacuum (0.4 mmHg) on a Kugelrohr apparatus at 90° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: L-lactide-ε-caprolactone copolymer pellets were prepared by carrying out the same procedures as described in Preparation Example 1 except that 216 g of L-lactide was replaced by 108 g of L-lactide and 108 g of ε-caprolactone. The copolymer obtained had an average molecular weight of 70,000. The copolymer obtained

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: L-lactide-glycolide copolymer pellets were prepared by carrying out the same procedures as described in Preparation Example 1 except that 216 g of L-lactide was replaced by 108 g of L-lactide and 108 g of glycolide. The copolymer obtained had an average molecular weight of 100,000. The copolymer obtained